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A cloud model target damage effectiveness assessment algorithm based on spatio-temporal sequence finite multilayer fragments dispersion
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作者 Hanshan Li Xiaoqian Zhang Junchai Gao 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2024年第10期48-64,共17页
To solve the problem of target damage assessment when fragments attack target under uncertain projectile and target intersection in an air defense intercept,this paper proposes a method for calculating target damage p... To solve the problem of target damage assessment when fragments attack target under uncertain projectile and target intersection in an air defense intercept,this paper proposes a method for calculating target damage probability leveraging spatio-temporal finite multilayer fragments distribution and the target damage assessment algorithm based on cloud model theory.Drawing on the spatial dispersion characteristics of fragments of projectile proximity explosion,we divide into a finite number of fragments distribution planes based on the time series in space,set up a fragment layer dispersion model grounded in the time series and intersection criterion for determining the effective penetration of each layer of fragments into the target.Building on the precondition that the multilayer fragments of the time series effectively assail the target,we also establish the damage criterion of the perforation and penetration damage and deduce the damage probability calculation model.Taking the damage probability of the fragment layer in the spatio-temporal sequence to the target as the input state variable,we introduce cloud model theory to research the target damage assessment method.Combining the equivalent simulation experiment,the scientific and rational nature of the proposed method were validated through quantitative calculations and comparative analysis. 展开更多
关键词 Target damage Cloud model Fragments dispersion effectiveness assessment spatio-temporal sequence
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Hybrid Effects on MHD Mixed Convective Boundary Layer Flow through a Sloped Plate in Existence of Nanofluid-Saturated Porous Medium
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作者 Md. Nasir Uddin Abdul Halim Bhuiyan +1 位作者 Zahurul Islam Tahmina Tahrim 《Journal of Applied Mathematics and Physics》 2024年第9期3037-3052,共16页
This study examines the effects of heat, mass, and boundary layer assumptions-based nanoparticle characteristics on the hybrid effects of using MHD in conjunction with mixed convective flow through a sloped vertical p... This study examines the effects of heat, mass, and boundary layer assumptions-based nanoparticle characteristics on the hybrid effects of using MHD in conjunction with mixed convective flow through a sloped vertical pore plate in the existence of medium of porous. Physical characteristics such as thermo-diffusion, injection-suction, and viscous dissipation are taken into consideration, in addition to an equally distributed magnetic force utilized as well in the completely opposite path of the flow. By means of several non-dimensional transformations, the momentum, energy, concentration, and nanoparticle volume fraction equations under investigation are converted in terms of nonlinear boundary layer equations and computationally resolved by utilizing the sixth-order Runge-Kutta strategy in combination together with the iteration of Nachtsheim-Swigert shooting procedure. By contrasting the findings produced for a few particular examples with those found in the published literature, the correctness of the numerical result is verified, and a rather good agreement is found. Utilizing various ranges of pertinent factors, computing findings are determined not only regarding velocity, temperature, and concentration as well as nanoparticle fraction of volume but also concerning with local skin-friction coefficient, local Nusselt and general Sherwood numbers associated with nanoparticle Sherwood number. The findings of the study demonstrate that increasing the fluid suction parameter decreases the velocity and temperature of the flow field in conjunction with concentration and has a variable impact on the nanoparticle fraction of volume, despite an increasing behavior in the local skin friction coefficient and local Nusselt as well as general Sherwood numbers and an increasing behavior in the local nanoparticle Sherwood number. Furthermore, enhancing a Schmidt number leads to a reduction in the local nanoparticle Sherwood number and a rise in the nanoparticle proportion of volume. Along with concentration, it also reduces temperature and velocity. However, it also raises the local Sherwood and Nusselt numbers and reduces the local skin friction coefficient. 展开更多
关键词 Hybrid effects mixed Convection MHD NANOFLUID Viscous Dissipation
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Synergistic anionic/zwitterionic mixed surfactant system with high emulsification efficiency for enhanced oil recovery in low permeability reservoirs 被引量:1
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作者 Hai-Rong Wu Rong Tan +6 位作者 Shi-Ping Hong Qiong Zhou Bang-Yu Liu Jia-Wei Chang Tian-Fang Luan Ning Kang Ji-Rui Hou 《Petroleum Science》 SCIE EI CAS CSCD 2024年第2期936-950,共15页
Emulsification is one of the important mechanisms of surfactant flooding. To improve oil recovery for low permeability reservoirs, a highly efficient emulsification oil flooding system consisting of anionic surfactant... Emulsification is one of the important mechanisms of surfactant flooding. To improve oil recovery for low permeability reservoirs, a highly efficient emulsification oil flooding system consisting of anionic surfactant sodium alkyl glucosyl hydroxypropyl sulfonate(APGSHS) and zwitterionic surfactant octadecyl betaine(BS-18) is proposed. The performance of APGSHS/BS-18 mixed surfactant system was evaluated in terms of interfacial tension, emulsification capability, emulsion size and distribution, wettability alteration, temperature-resistance and salt-resistance. The emulsification speed was used to evaluate the emulsification ability of surfactant systems, and the results show that mixed surfactant systems can completely emulsify the crude oil into emulsions droplets even under low energy conditions. Meanwhile,the system exhibits good temperature and salt resistance. Finally, the best oil recovery of 25.45% is achieved for low permeability core by the mixed surfactant system with a total concentration of 0.3 wt%while the molar ratio of APGSHS:BS-18 is 4:6. The current study indicates that the anionic/zwitterionic mixed surfactant system can improve the oil flooding efficiency and is potential candidate for application in low permeability reservoirs. 展开更多
关键词 Anionic/zwitterionic mixed surfactant system EMULSIFICATION Synergistic effect Low permeability reservoir Enhanced oil recovery
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Effectively modulating spatial vortex four-wave mixing in a diamond atomic system
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作者 巴诺 姜明奇 +4 位作者 费金友 王丹 蒋海林 王磊 王海华 《Chinese Physics B》 SCIE EI CAS CSCD 2024年第4期473-478,共6页
Due to the spatial characteristics of orbital angular momentum,vortex fields can be applied in the fields of quantum storage and quantum information.We study the realization of spatially modulated vortex fields based ... Due to the spatial characteristics of orbital angular momentum,vortex fields can be applied in the fields of quantum storage and quantum information.We study the realization of spatially modulated vortex fields based on four-wave mixing in a four-level atomic system with a diamond structure.The intensity and spiral phase of the vortex field are effectively transferred to the generated four-wave mixing field.By changing the detuning of the probe field,the phase and intensity of the generated vertex four-wave mixing field can be changed.When the probe field takes a large detuning value,the spatial distribution of the intensity and phase of the vertex four-wave mixing field can be effectively tuned by adjusting the Rabi frequency or detuning value of the coupled field.At the same time,we also provide a detailed explanation based on the dispersion relationship,and the results agree well with our simulation results. 展开更多
关键词 coherent optical effects four-wave mixing orbital angular momentum
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Mixed-field effect at the hyperfine level of^(127)I^(79)Br in its rovibronic ground state:Toward field manipulation of cold molecules
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作者 包正斌 王得富 +2 位作者 邵旭萍 黄云霞 杨晓华 《Chinese Physics B》 SCIE EI CAS CSCD 2023年第12期312-317,共6页
The mixed-field effect at the hyperfine level of the rovibronic ground state of the^(127)I^(79)Br(X^(1)Σ,v=0,J=0)molecule is computed on the J-I uncoupled basis of|JM_(J)I_(1)M_(1)I_(2)M_(2)>,where J is the molecu... The mixed-field effect at the hyperfine level of the rovibronic ground state of the^(127)I^(79)Br(X^(1)Σ,v=0,J=0)molecule is computed on the J-I uncoupled basis of|JM_(J)I_(1)M_(1)I_(2)M_(2)>,where J is the molecular total angular momentum excluding nuclear spin,M_J is the projection number of J,I_(1) and I_(2) are the nuclear spins of the iodine and bromine atoms,and M_(1) and M_(2) are the projection numbers of I_(1) and I_(2),respectively.When the two applied electric and magnetic fields are parallel,the perturbations are rare and only one perturbation is observed in a relatively large field regime in our computation range.However,when the two fields are off-parallel,the perturbations increase significantly and some sublevels show the Feshbach-like resonance phenomenon.Therefore,such sublevels transit between weak-field seeking and strong-field seeking repeatedly,which can be utilized to enhance or suppress cold molecular collision and chemical reaction rates.Such behavior of the molecular hyperfine structure in the mixed off-parallel fields may also be utilized to construct an electric-field-assisted anti-Helmholtz magnetic trap for cold molecules and to realize evaporative cooling of cold molecules(sub-mK)into the ultracold regime(μK). 展开更多
关键词 hyperfine structure mixed Zeeman and Stark effect evaporative cooling IBr molecule
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Measurement of the Thermic Effect of Food in a Chinese Mixed Diet in Young People
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作者 TIAN Ying CAO Hong Peng +5 位作者 HUAN Yu Ping GONG Jia Wei YUAN Kai Hua CHEN Wen Zhuo HU Jing SHI Yu Fei 《Biomedical and Environmental Sciences》 SCIE CAS CSCD 2023年第7期585-594,共10页
Objective To determine the thermic effect of food(TEF)in a Chinese mixed diet in young people.Methods During the study,the participants were weighed and examined for body composition every morning.The total energy exp... Objective To determine the thermic effect of food(TEF)in a Chinese mixed diet in young people.Methods During the study,the participants were weighed and examined for body composition every morning.The total energy expenditure(TEE)of the participants was measured by the doubly labeled water method for 7 days,and during this period,basal energy expenditure was measured by indirect calorimetry and physical activity energy expenditure was measured by an accelerometer.The value obtained by subtracting basal energy expenditure and physical activity energy expenditure from TEE was used to calculate TEF.Results Twenty healthy young students(18–30 years;10 male)participated in the study.The energy intake of the participants was not significantly different from the Chinese Dietary Reference Intake of energy(P>0.05).The percentage of energy from protein,fat and carbohydrate were all in the normal range.The intakes of fruits,milk and dietary fiber of the participants were significantly lower than those in the Chinese Dietary Guidelines(P<0.05).There was no significant difference in the body weight of the participants during the experiment(P>0.05).When adjusted for body weight,there was no significant difference in either TEE or basal energy expenditure between the male and female participants(P>0.05).In addition,there was no significant difference in physical activity energy expenditure and TEF between the male and female participants(P>0.05).The percentage of TEF in TEE was 8.73%.Conclusion The percentage of TEF in TEE in a Chinese mixed diet in young people was significantly lower than 10%(P<0.001).A value of 10%is usually considered to be the TEF in mixed diets as a percentage of TEE. 展开更多
关键词 Thermic effect of food Chinese mixed diet Total energy expenditure Basal energy expenditure Physical activity energy expenditure Doubly labeled water
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Mixed-Effects Parametric Proportional Hazard Model with Generalized Log-Logistic Baseline Distribution
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作者 Maryrose Wausi Peter Samuel Musili Mwalili +1 位作者 Anthony Kibira Wanjoya Abdsalam Hassan Muse 《Journal of Data Analysis and Information Processing》 2023年第2期81-102,共22页
Clustered survival data are widely observed in a variety of setting. Most survival models incorporate clustering and grouping of data accounting for between-cluster variability that creates correlation in order to pre... Clustered survival data are widely observed in a variety of setting. Most survival models incorporate clustering and grouping of data accounting for between-cluster variability that creates correlation in order to prevent underestimate of the standard errors of the parameter estimators but do not include random effects. In this study, we developed a mixed-effect parametric proportional hazard (MEPPH) model with a generalized log-logistic distribution baseline. The parameters of the model were estimated by the application of the maximum likelihood estimation technique with an iterative optimization procedure (quasi-Newton Raphson). The developed MEPPH model’s performance was evaluated using Monte Carlo simulation. The Leukemia dataset with right-censored data was used to demonstrate the model’s applicability. The results revealed that all covariates, except age in PH models, were significant in all considered distributions. Age and Townsend score were significant when the GLL distribution was used in MEPPH, while sex, age and Townsend score were significant in MEPPH model when other distributions were used. Based on information criteria values, the Generalized Log-Logistic Mixed-Effects Parametric Proportional Hazard model (GLL-MEPPH) outperformed other models. 展开更多
关键词 Survival Analysis Generalized Log-Logistic PARAMETRIC Proportional Hazard mixed-effects Monte Carlo Maximum Likelihood Estimation
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Effect of Mixed Silage of Alhagi sparsifolia and Medicago sativa at Initial Flowering Stage on Degradation
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作者 蒋慧 应璐 +2 位作者 张秀萍 陈宏伟 马金萍 《Agricultural Science & Technology》 CAS 2010年第11期4-6,113,共4页
[Objective] The influence of mixed silage of A.sparsifolia and M.sativa at initial flowering stage on degradation was studied to provide theoretical basis for production practice.[Method] Using A.sparsifolia and M.sat... [Objective] The influence of mixed silage of A.sparsifolia and M.sativa at initial flowering stage on degradation was studied to provide theoretical basis for production practice.[Method] Using A.sparsifolia and M.sativa at initial flowering stage as materials,the changes of in vitro degradation rate,gas production,pH value,ammoniacal nitrogen(NH3-N)and volatile fatty acid(VFA)content in degradation solution were analyzed by means of artificial rumen technique,and the effect of mixed silage of A.sparsifolia and M.sativa at initial flowering stage on degradation was studied in order to find out suitable mixed silage ratio of A.sparsifolia and M.sativa.[Result] Compared with single M.sativa,NH3-N content in degradation solution was very significantly decreased in the mixed silage of A.sparsifolia and M.sativa,and there was a reduction in gas production,while the content of acetic acid,propionic acid and butyric acid increased significantly;for the treatment of 70% A.sparsifolia and 30% M.sativa,NH3-N content(22.93 mmol/L)and gas production(40.50 ml)was lowest,while degradation rate(32.27%),acetic acid(5.48 mmol/L),propionic acid(2.08 mmol/L),butyric acid(2.52 mmol/L)and their total content(10.08 mmol/L)were highest,so its degradation effect was the best.[Conclusion] The mixed silage of A.sparsifolia and M.sativa at initial flowering stage could improve the utilization efficiency of protein and carbohydrate in M.sativa and the treatment of 70% A.sparsifolia and 30% M.sativa had the best degradation effect. 展开更多
关键词 A.sparsifolia M.sativa mixed silage Degradation effect
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Can a multistage approach improve individual tree mortality predictions across the complex mixed-species and managed forests of eastern North America?
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作者 Cen Chen John Kershaw Jr +1 位作者 Aaron Weiskittel Elizabeth McGarrigle 《Forest Ecosystems》 SCIE CSCD 2023年第1期21-30,共10页
Tree mortality plays a fundamental role in the dynamics of forest ecosystems,yet it is one of the most difficult phenomena to accurately predict.Various modeling strategies have been developed to improve individual tr... Tree mortality plays a fundamental role in the dynamics of forest ecosystems,yet it is one of the most difficult phenomena to accurately predict.Various modeling strategies have been developed to improve individual tree mortality predictions.One less explored strategy is the use of a multistage modeling approach.Potential improvements from this approach have remained largely unknown.In this study,we developed a novel multistage approach and compared its performance in individual tree mortality predictions with a more conventional approach using an identical individual tree mortality model formulation.Extensive permanent plot data(n=9442)covering the Acadian Region of North America and over multiple decades(1965–2014)were used in this study.Our results indicated that the model behavior with the multistage approach better depicted the observed mortality and showed a notable improvement over the conventional approach.The difference between the observed and predicted numbers of dead trees using the multistage approach was much smaller when compared with the conventional approach.In addition,tree survival probabilities predicted by the multistage approach generally were not significantly different from the observations,whereas the conventional approach consistently underestimated mortality across species and overestimated tree survival probabilities over the large range of DBH in the data.The new multistage approach also predictions of zero mortality in individual plots,a result not possible in conventional models.Finally,the new approach was more tolerant of modeling errors because it based estimates on ranked tree mortality rather than error-prone predicted values.Overall,this new multistage approach deserves to be considered and tested in future studies. 展开更多
关键词 Tree mortality modeling Mortality disaggregation mixed effect model Annualization mixed forests
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Numerical investigation of variable viscosities and thermal stratification effects on MHD mixed convective heat and mass transfer past a porous wedge in the presence of a chemical reaction 被引量:2
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作者 I. Muhaimin R. Kandasamy Azme B. Khamis 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI 2009年第11期1353-1364,共12页
An analysis is presented to investigate the effects of variable viscosities and thermal stratification on the MHD mixed convective heat and mass transfer of a viscous, incompressible, and electrically conducting fluid... An analysis is presented to investigate the effects of variable viscosities and thermal stratification on the MHD mixed convective heat and mass transfer of a viscous, incompressible, and electrically conducting fluid past a porous wedge in the presence of a chemical reaction. The wall of the wedge is embedded in a uniform nonDarcian porous medium in order to allow for possible fluid wall suction or injection. The governing boundary layer equations are written into a dimensionless form by similarity transformations. The transformed coupled nonlinear ordinary differential equations are solved numerically with finite difference methods. Numerical calculations up to the thirdorder level of truncation are carried out for different values of dimensionless parameters. The results are presented graphically, and show that the flow field and other quantities of physical interest are significantly influenced by these parameters. The results are compared with those available in literature, and show excellent agreement. 展开更多
关键词 variable viscosity chemical reaction non-Darcy flow mixed convection thermal stratification magnetic effect
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MECHANISM ANALYSIS OF THICKNESS EFFECT ON MIXED MODE Ⅰ/Ⅱ FRACTURE OF LC4-CS ALUMINUM ALLOY 被引量:2
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作者 H.R. Dong W.L. Guo 《Acta Metallurgica Sinica(English Letters)》 SCIE EI CAS CSCD 2004年第3期255-262,共8页
Mixed mode Ⅰ/Ⅱ fracture erperiments of LC4-CS aluminum alloy were conductedby using tension--shear specimens with thicknesses of 2, 4, 8 and 14mm. Fracturemechanisms of thickness effect on mixed mode Ⅰ/Ⅱ fracture ... Mixed mode Ⅰ/Ⅱ fracture erperiments of LC4-CS aluminum alloy were conductedby using tension--shear specimens with thicknesses of 2, 4, 8 and 14mm. Fracturemechanisms of thickness effect on mixed mode Ⅰ/Ⅱ fracture were first examined fromfracture surface morphology to correlate with the macroscopic fracture behavior andstress state. It is found that specimen thickness has a strong influence on mixed modefracture. As thickness varies from thin to thick the macroscopic fracture surfacesappear the characteristics of plane stress state (2mm, 4mm--thick specimen), three--dimensional stress state (8mm--thick specimens), and plane strain state (14mm--thickspecimens), respectively. The specimens of all kinds of thicknesses are typical of ten-sile type failure under mode Ⅰ loading condition and shear type failure under mode Ⅱloading condition. Two distinct features coexist on the fracture surfaces under mixedmode loading conditions, and the corresponding proportion varies with loading mix-ity. Void--growth processes are the failure mechanism in both predominately tensile-and shears--type fractures. The size and depth of dimples on the fracture surface varygreatly with thickness. Therefore, it is extraordinary necessary to take into accountthe thickness effect when a mixed mode fracture criterion is being established. 展开更多
关键词 LC4-CS aluminum alloy mixed mode Ⅰ/Ⅱ fracture thickness effect macroscopic fracture appearance SEM
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Synergistic Effect in Mixed Capillary Gas Chromatographic Stationap Phases Containing Heptakis(2,3,6-tri-o-pentyl)-β-cyclodextrin and Dibenzo-18-crown-6 被引量:1
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作者 Li Ming YUAN Ruo Nong FU +3 位作者 Xue Xian CHEN Shi Hong GUl Rong Ji DAI (Chemistry Department of Yunnan Normal University.Kunming 650092)(Department of Chemical Engineering.Beijing institute of Technology,BEijing 100081)(Solar Energy Research Institute ofyunna 《Chinese Chemical Letters》 SCIE CAS CSCD 1999年第3期223-226,共4页
used-silical capillary columns containing heptakis(2、3、6-tri-o-pentyl)-β-cyclodextrinand dibenzo-18-crown-6 were prepared.By studying the selectivity of mixed stationary phases forsome solute pairs.as well a... used-silical capillary columns containing heptakis(2、3、6-tri-o-pentyl)-β-cyclodextrinand dibenzo-18-crown-6 were prepared.By studying the selectivity of mixed stationary phases forsome solute pairs.as well as comparing with the heptakis(2.3、6-tri-O-pentyl)-β-cyclodextrin and thedibenzo-18-crown-6 used as individual stationary phase、the synergistic effects were observed.These effects were affected by the column temperature.mixed ratio and linear velocity of carrier gas. 展开更多
关键词 Gas chromatography mixed stationary phase synergistic effect heptakis(2.3.6-tri-o-pentyl)-β-cyclodextrin DIBENZO-18-CROWN-6
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Additive mixed models to study the effect of tree age and climatic factors on stem radial growth of Eucalyptus trees 被引量:1
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作者 Sileshi F.Melesse Temesgen Zewotir 《Journal of Forestry Research》 SCIE CAS CSCD 2020年第2期463-473,共11页
The effect of tree age and climatic variables on stem radial growth of two hybrid clones of Eucalyptus was determined using longitudinal data from eastern South Africa.The stem radius of was measured weekly as the res... The effect of tree age and climatic variables on stem radial growth of two hybrid clones of Eucalyptus was determined using longitudinal data from eastern South Africa.The stem radius of was measured weekly as the response variable.In addition to tree age,average weekly temperature,solar radiation,relative humidity and wind speed were simultaneously recorded with total rainfall at the site.An additive mixed effects model that incorporates a non-parametric smooth function was used.The results of the analysis indicate that the relationship between stem radius and each of the covariates can be explained by nonlinear functions.Models that account for the effect of clone and season together with their interaction in the parametric part of the additive mixed model were also fitted.The interaction between clone and season was not significant in all cases.For analyzing the joint effect all the covariates,additive mixed models that included two or more covariates were fitted.A significant effect of tree age was found in all cases.Although tree age was the key determinant of stem radial growth,weather variables also had a significant effect that was dependent on season. 展开更多
关键词 Additive mixed effects Dendrometer trial Parametric modelling Penalized splines Weather variables
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Effects of Nitrogen Addition on the Mixed Litter Decomposition in Stipa baicalensis Steppe in Inner Mongolia 被引量:1
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作者 Wenya Li Wenchao Yu +2 位作者 Long Bai Hongmei Liu Dianlin Yang 《American Journal of Plant Sciences》 2016年第3期547-561,共15页
During the past two centuries, global changes (i.e., enhanced nitrogen deposition) have exerted profound effects on ecological processes of steppe ecosystems. We used litterbag method and mixed litters of three differ... During the past two centuries, global changes (i.e., enhanced nitrogen deposition) have exerted profound effects on ecological processes of steppe ecosystems. We used litterbag method and mixed litters of three different plant species tissues (Stipa baicalensis: Sb, Leymus chinensis: Lc and Artemisia frigid: Af), endemic to Stipa baicalensis Steppe, and measured the mass loss of mixtures over 417 days under the N addition treatment. We studied the effect of N addition (N0: no N addition;N15: 1.5 g N/m<sup>2</sup>·a;N30: 3.0 g N/m<sup>2</sup>·a;N50: 5.0 g N/m<sup>2</sup>·a;N100: 10.0 g N/m<sup>2</sup>·a;N150: 15.0 g N/m<sup>2</sup>·a) on the rate of mixed litter decomposition and nutrient dynamics change. The decomposition constant (k) of leaf mixtures was higher than that of root mixtures. The k values of leaf mixed combinations were 0.880 (Sb + Lc), 1.231 (Lc + Af), 1.027 (Sb + Lc + Af), respectively. The k value of stem was 0.806 (Lc + Af) and the root mixed combinations were 0.665 (Sb + Lc), 0.979 (Lc + Af) and 1.164 (Sb + Lc + Af), respectively. The results indicated that N addition had significantly effect on the mixed litter decomposition and nutrient releasing. The rate of plant tissues litter decomposition had different response to N addition. In the context of N addition, litter decomposition rate and nutrient dynamics were changed by synthetic effect of decaying time, specie types and N addition dose. Our findings suggested that prairie plants may adapt to environmental change by adjusting litter quality, thus retaining the stability of the steppe ecosystem. 展开更多
关键词 GRASSLAND Litter Decomposition mixed effect N Addition Mass Loss Nutrient Dynamics
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Experiment on the Fattening Effects of Mixed Silage of Wolfberry Branches on Hybrid 被引量:1
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作者 Youren DING Hua YUN +3 位作者 Ning'an MEI Jianning DING Yuping YAN Deyun YANG 《Agricultural Biotechnology》 CAS 2019年第6期57-58,67,共3页
[Objectives] This study was conducted to use the feeding value of wolfberry branches and to provide a basis for the rational use of its active ingredients and nutrients and the development of new feed resources. [Meth... [Objectives] This study was conducted to use the feeding value of wolfberry branches and to provide a basis for the rational use of its active ingredients and nutrients and the development of new feed resources. [Methods] Wolfberry branches and whole-plant corn were used to make mixed silage of wolfberry branches, which replaced different proportions of whole-plant corn silage for feeding hybrid mutton sheep, and the feeding effect of the mixed silage of wolfberry branches on hybrid mutton sheep was analyzed, which provides a technical basis for rational utilization of mulberry resources to ruminants. A single factor feeding comparison experiment was carried out. 32 hybrid mutton sheep of 8 months old with conform gender, age, body weight, physiological state and feeding management level were selected and divided into two groups, 16 in each group. [Results] The gross output value of weight gain of the experimental group was 18.06 yuan, which was higher than the CK(12.97 yuan) by 5.09 yuan. [Conclusions] The addition of the mixed silage of wolfberry branches to the diet had a positive effect on the increase of the weight gain of the hybrid mutton sheep and the reduction of the feed conversion ratio compared with the single whole-plant corn silage. 展开更多
关键词 Wolfberry branches mixed silage Hybrid mutton sheep Fattening effect
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Experiment on the Fattening Effects of Mixed Silage of Mulberry Branches and Leaves on Hybrid Mutton Sheep 被引量:1
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作者 Zhanlin WANG Ning'an MEI +2 位作者 Guoling ZHANG Jianning DING Yuping YAN 《Agricultural Biotechnology》 CAS 2019年第6期42-43,共2页
[Objectives] This study was conducted to investigate the effect of mixed silage of mulberry branches and leaves on the production performance of Tan Han hybrid mutton sheep and explore the feasibility in production. [... [Objectives] This study was conducted to investigate the effect of mixed silage of mulberry branches and leaves on the production performance of Tan Han hybrid mutton sheep and explore the feasibility in production. [Methods] Twenty-six Tan Han hybrid mutton sheep were selected and divided into two groups, 13 in each group. The experimental group was fed with the mixed silage and the control group(CK) was fed with whole-plant corn silage. [Results] The average daily weight gain per sheep of the experimental group was 9.2% higher than that of the CK(P<0.05), and the feed conversion ratio was decreased by 6.98%(P<0.05). The average daily weight gain per sheep in the 30 d improved the gross profit by 7.75 yuan, which meant an increase of 16.32%. [Conclusions] The mulberry mixed silage is feasible in the production, and it could significantly improve the production performance of the hybrid mutton sheep. 展开更多
关键词 Mulberry branches and leaves mixed silage Hybrid mutton sheep Fattening effect
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Modelling tree mortality across diameter classes using mixedeffects zero-inflated models 被引量:4
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作者 Yang Li Xingang Kang +1 位作者 Qing Zhang Weiwei Guo 《Journal of Forestry Research》 SCIE CAS CSCD 2020年第1期131-140,共10页
The mortality of trees across diameter class model is a useful tool for predicting changes in stand structure.Mortality data commonly contain a large fraction of zeros and general discrete models thus show more errors... The mortality of trees across diameter class model is a useful tool for predicting changes in stand structure.Mortality data commonly contain a large fraction of zeros and general discrete models thus show more errors.Based on the traditional Poisson model and the negative binomial model,different forms of zero-inflated and hurdle models were applied to spruce-fir mixed forests data to simulate the number of dead trees.By comparing the residuals and Vuong test statistics,the zero-inflated negative binomial model performed best.A random effect was added to improve the model accuracy;however,the mixed-effects zero-inflated model did not show increased advantages.According to the model principle,the zeroinflated negative binomial model was the most suitable,indicating that the"0"events in this study,mainly from the sample"0",i.e.,the zero mortality data,are largely due to the limitations of the experimental design and sample selection.These results also show that the number of dead trees in the diameter class is positively correlated with the number of trees in that class and the mean stand diameter,and inversely related to class size,and slope and aspect of the site. 展开更多
关键词 Tree mortality mixed forest Zero-inflated model Hurdle model mixed-effects
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Competitive effect, but not competitive response, varies along a climatic gradient depending on tree species identity
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作者 Teresa Valor Lluís Coll +9 位作者 David I.Forrester Hans Pretzsch Miren del Río Kamil Bielak Bogdan Brzeziecki Franz Binder Torben Hilmers Zuzana Sitková Roberto Tognetti Aitor Ameztegui 《Forest Ecosystems》 SCIE CSCD 2024年第2期142-151,共10页
Background: Understanding the role of species identity in interactions among individuals is crucial for assessing the productivity and stability of mixed forests over time. However, there is limited knowledge concerni... Background: Understanding the role of species identity in interactions among individuals is crucial for assessing the productivity and stability of mixed forests over time. However, there is limited knowledge concerning the variation in competitive effect and response of different species along climatic gradients. In this study, we investigated the importance of climate, tree size, and competition on the growth of three tree species: spruce(Picea abies), fir(Abies alba), and beech(Fagus sylvatica), and examined their competitive response and effect along a climatic gradient.Methods: We selected 39 plots distributed across the European mountains with records of the position and growth of 5,759 individuals. For each target species, models relating tree growth to tree size, climate and competition were proposed. Competition was modelled using a neighbourhood competition index that considered the effects of inter-and intraspecific competition on target trees. Competitive responses and effects were related to climate.Likelihood methods and information theory were used to select the best model.Results: Our findings revealed that competition had a greater impact on target species growth than tree size or climate. Climate did influence the competitive effects of neighbouring species, but it did not affect the target species? response to competition. The strength of competitive effects varied along the gradient, contingent on the identity of the interacting species. When the target species exhibited an intermediate competitive effect relative to neighbouring species, both higher inter-than intraspecific competitive effects and competition reduction occurred along the gradient. Notably, species competitive effects were most pronounced when the target species' growth was at its peak and weakest when growing conditions were far from their maximum.Conclusions: Climate modulates the effects of competition from neighbouring trees on the target tree and not the susceptibility of the target tree to competition. The modelling approach should be useful in future research to expand our knowledge of how competition modulates forest communities across environmental gradients. 展开更多
关键词 Competition coefficient Competition reduction Interspecific competition Intraspecific competition mixing effects mixed species forest Neighbourhood models Plant-plant interactions
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Nonlinear mixed-effects height to crown base and crown length dynamic models using the branch mortality technique for a Korean larch( Larix olgensis ) plantations in northeast China 被引量:8
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作者 Weiwei Jia Dongsheng Chen 《Journal of Forestry Research》 SCIE CAS CSCD 2019年第6期2095-2109,共15页
Korean larch(Larix olgensis)is one of the main tree species for aff orestation and timber production in northeast China.However,its timber quality and growth ability are largely infl uenced by crown size,structure and... Korean larch(Larix olgensis)is one of the main tree species for aff orestation and timber production in northeast China.However,its timber quality and growth ability are largely infl uenced by crown size,structure and shape.The majority of crown models are static models based on tree size and stand characteristics from temporary sample plots,but crown dynamic models has seldom been constructed.Therefore,this study aimed to develop height to crown base(HCB)and crown length(CL)dynamic models using the branch mortality technique for a Korean larch plantation.The nonlinear mixed-eff ects model with random eff ects,variance functions and correlation structures,was used to build HCB and CL dynamic models.The data were obtained from 95 sample trees of 19 plots in Meng JiaGang forest farm in Northeast China.The results showed that HCB progressively increases as tree age,tree height growth(HT growth)and diameter at breast height growth(DBH growth).The CL was increased with tree age in 20 years ago,and subsequently stabilized.HT growth,DBH growth stand basal area(BAS)and crown competition factor(CCF)signifi cantly infl uenced HCB and CL.The HCB was positively correlated with BAS,HT growth and DBH growth,but negatively correlated with CCF.The CL was positively correlated with BAS and CCF,but negatively correlated with DBH growth.Model fi tting and validation confi rmed that the mixed-eff ects model considering the stand and tree level random eff ects was accurate and reliable for predicting the HCB and CL dynamics.However,the models involving adding variance functions and time series correlation structure could not completely remove heterogeneity and autocorrelation,and the fi tting precision of the models was reduced.Therefore,from the point of view of application,we should take care to avoid setting up over-complex models.The HCB and CL dynamic models in our study may also be incorporated into stand growth and yield model systems in China. 展开更多
关键词 Larix olgensis plantation Height to CROWN BASE CROWN LENGTH Branch MORTALITY technique NONLINEAR mixed-eff ects models
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GROWTH EFFECT OF DAHURIAN LARCH-MANCHURIAN ASH MIXED FORESTS
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作者 王凤霞 《Journal of Northeast Forestry University》 SCIE CAS CSCD 1996年第2期20-24,共5页
With the method of stem analyses by the microscope, the xylem’s accumulations atdifferent ages were quantitatively studied using the data of typical plant association for Dahurianlarch (Larix gmelini Rupr) and Manchu... With the method of stem analyses by the microscope, the xylem’s accumulations atdifferent ages were quantitatively studied using the data of typical plant association for Dahurianlarch (Larix gmelini Rupr) and Manchurian ash (Fraxinus mandshurica Rupr) mixed forests. Thedeveloping process for this important mixed forest type in the study area was systematically established. The result showed that in the artificial stand of Dahurian larch mixed with naturalManchurian ash. only those which have the same origin as Dahurian larch can grow up before theclosing of stand and form the components of the main layers. After 24 years seif-thinning, when theywere 29 years old, Dahurian larch would be at the stage of no self-thinning. At last the stand woulddevelop to the broad-leaved forests dominating with the Manchurian ash. 展开更多
关键词 mixed FOREST Dahurian LARCH Manchurian ASH SPECIES RELATION Growth effect
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